Multiple vertical diaphragm electrolytic cell having gas-bubble guiding partition plates

ABSTRACT

A multiple vertical diaphragm type electrolytic cell which is fitted with a plurality of gas-bubble guiding partition plates and/or in a style of up-and-down stages to the confront surfaces of electrodes and/or in every anode chamber and/or cathode chamber so as to form a perpendicular gas-bubble passageway at the vertical central plane position of said electrode chamber; wherein the gas-bubble guiding plates incline upwards toward the gas-bubble passageway. The guiding plates are constructed of heat-resistant synthetic resin and are slightly separated from the walls of the electrodes.

United States Patent [191 Shibata et a1.

[54] MULTIPLE VERTICAL DIAPHRAGM ELECTROLYTIC CELL HAVING GAS-BUBBLE GUIDING PARTITION PLATES [75] Inventors; Hiroshi Shibata; Yoshikazu Kokubu;

Isao Okazaki, all of Iwaki, Japan Kureha Kagaku Kogyo Kabushiki Kaisha, Tokyo, Japan [22] Filed: Apr. 16, 1974 [21] Appl. No.: 461,295

[73] Assignee:

[30] Foreign Application Priority Data Apr. 19, 1973 Japan 48-44415 [52] US. Cl. 204/258; 204/266; 204/270; 204/278; 204/283 [51] Int. C1. C25B 9/00 [58] Field of Search 204/258, 266, 278, 283, 204/256, 270

[56] References Cited UNITED STATES PATENTS 1,427,236 8/1922 Sherwood 204/266 X Ill III'IIII 'n\\u-:mw.n :IIIIIIIIII VIIII'IIIIIIIIIII 'IIIIIIIIIIIIIIII Dec. 30, 1975 1,771,091 7/1930 Lawaczeck .1 204/252 1,835,955 12/1931 Lawaczeck 204/258 2,682,505 6/1954 Greco 204/256 X 2,691,628 10/1954 Aannerud 204/258 X 3,855,104 12/1974 Messner 204/258 X Primary ExaminerT. Tung Assistant ExaminerW. 1. Solomon Attorney, Agent, or FirmFlynn & Frishauf [57] ABSTRACT A multiple vertical diaphragm type electrolytic cell which is fitted with a plurality of gas-bubble guiding partition plates and/or in a style of up-and-down stages to the confront surfaces of electrodes and/or in every anode chamber and/or cathode chamber so as to form a perpendicular gas-bubble passageway at the vertical central plane position of said electrode chamber; wherein the gas-bubble guiding plates incline upwards toward the gas-bubble passageway. The guiding plates are constructed of heat-resistant synthetic resin and are slightly separated from the walls of the electrodes.

11 Claims, 3 Drawing Figures US. Patent Dec. 30, 1975 Sheet 1 of2 3,930,151

FIG.

Sheet 2 0f 2 3,930,151

US. Patent Dec. 30, 1975 F l G. 3

is WH MULTIPLE VERTICAL DIAPHRAGM ELECTROLYTIC CELL HAVING GAS-BUBBLE GUIDING PARTITION PLATES This invention relates to an improvement on a multiple vertical diaphragm type electrolytic cell.

It is well known that in the electrolytic cell, wherein gases are evolved on the surface of the electrodes, for instance, the type used to manufacturing chlorine and caustic alkali by the electrolysis of an aqueous solution of alkali chloride, hydrogen and oxygen by the electrolysis of water and persulfate and hydrogen peroxide by the electrolysis of an aqueous solution of sulfuric acid, gases evolved all over the surfaces of the electrodes reduce the efficiency of the electrolytic cell. Particularly in a multiple vertical diaphragm type electrolytic cell wherein the cathodes and anodes are displaced close to the diaphragms, not only gases evolved on the surfaces of the electrodes are hardly released therefrom, but also gases generated at the lower part of the vertical electrodes rise up the side walls thereof, causing the upper part to be covered with a large amount of gases. Furthermore, some of the evolved gases intrude into the diaphragms, thus unavoidably decreasing the electrolyzing efficiency. In such case, the deeper the cell, or the larger the electrode current, the more prominent the efficiency drop. Though it may be contemplated to try to elevate productivity per unit floor spaces of an electrolysis plant using deeper cells or increasing current density, such attempts are naturally subject to large limitations It is accordingly an object of this invention to provide a multiple vertical diaphragm type electrolytic cell which can increase current density over the level attainable in the past despite the unavoidable evolution of gas bubbles.

Another object of the invention is to provide a multiple vertical diaphragm type electrolytic cell which enables to use a deeper cell than in the prior art.

. SUMMARY OF THE INVENTION These objects can be attained in accordance with the present invention by providing a plurality of upward by inclined gas-bubble guiding partition plates attached in a vertical direction to the mutually facing walls of the electrodes disposed on the opposite inner sides of the respective anode and/or cathode chambers assembled in an alternate formation so as to define gas-bubble passageways along the vertical central plane position of the electrode chambers.

BRIEF DESCRIPTION OF THE DRAWINGS Other important objects and advantageous features of this invention will be apparent from the following description and accompanying drawings, wherein for the present purpose of illustration only, specific embodiments of this invention are set forth in detail.

In the drawings:

FIG. I is a schematic oblique view, partly in section, of the main part of an electrolytic cell improved by this invention;

FIG. 2 is a schematic cross sectional view of the interior of one of the unit anode chambers included in the cell of FIG. 1; and

FIG. 3 is a schematic cross sectional view of an original unit cell of Example 2 constructed in a multiple vertical diaphragm type cell for electrolysis of water.

DETAILED DESCRIPTION FIG. 1 represents a multiple vertical diaphragm type electrolytic cell of brine improved by this invention. In the cell 1, an anode 2 is separated by a vertical diaphragm 4 from an adjacent cathode chamber 3. An anode plate 5 and a cathode wire net 6 are erected close to both sides of the diaphragm 4. The anode chamber 2 has, as shown in FIG. 2 with greater detail, a plurality of gasbubble guiding partition plates 7 inclined upwardly relative to the vertical central plane position of the anode chamber 2 and attached in a vertical direction to the mutually facing walls of the anode plates 5 disposed on the opposite inner sides of the anode chamber 2. Said gas-bubble guiding partition plates 7 have such a width as enables said plates 7 collectively to define a vertical gas-bubble passageway 8 along the vertical central plane position of the anode chamber 2.

Bubbles of chlorine gas evolved on the surfaces of the anode plates 5 move along the guiding partition plates 7 to gather in the vertical gas-bubble passageway 8, and then rise upward. Accordingly, not only gas bubbles generated at the lower part of the anode plates 5 are prevented from being attached to the surfaces of the upper part of said plates 5 to obstruct electrolysis, but also streams of gases rising through the gas-bubble passageway 8 induce the release of gas-bubbles from the surfaces of the anode plates 5 as well as from the interior of the diaphragms 4, resulting in that the efficiency of electrolysis is greatly increased.

The lower end of each guiding partition plate 7 may be fitted to, or slightly separated from, the surfaces of the anode plates 5. While the guiding partition plate 7 is generally prepared from a chemically stable heatresistant synthetic resin material such as chlorinated polyvinyl chloride, it is also possible to form the guiding partition plate 7 of the same electrically conductive material as the anode plate 5, thereby partly conducting electrolytic current to the chamber through said guiding partition plate 7.

As seen from FIG. 1, a plurality of gas-bubble guiding partition plates 7a are also provided in the cathode chamber 3 as in the anode chamber 2, thereby facilitating the release of bubbles of hydrogen gas from the surfaces of the wire net cathodes 6 soon after the bubbles are evolved thereon. While it is generally preferred to provide gas-bubble guiding partition plates 7 and 7a in both anode and cathode chambers 2 and 3, it is possible to use said partition plates 7 or 7a in either of the anode and cathode chambers 2 and 3, where gases evolved in the anode or cathode chamber 2 or 3 are extremely corrosive, or the material resistant to gas corrosion is considerably expensive, where the anode 5 or the cathode 6 is so constructed as to attain the easy release of gas bubbles therefrom, or where gas bubbles do not substantially arise in the anode or cathode chamber.

The number, interval and width of the gas-bubble guiding partition plates 7 and 7a are suitably chosen to match the depth of a cell bath and the electrode current density.

Further, it is not always necessary to arrange the guiding partition plates equidistantly in a vertical direction. For example, it sometimes proves very effective to arrange the lower guiding partition plates at a larger interval and the upper ones at a smaller interval. The vertical gas-bubble passageway need not always have a uniform width. For example, with an electrolytic cell having a deep bath and operated with high current density, it is advised to form said passageway with a slightly larger width toward the top. Neither is it always necessary to fit the gas-bubble guiding partition plates to the anode and the cathode in a horizontal position. Further, the guiding partition plates need not always be plane, but can be slightly curved or refracted lengthwise or crosswise.

The multiple vertical diaphragm type electrolytic cell improved by this invention enables gas bubbles evolved on the surfaces of the electrodes to be quickly released therefrom and prevents gas bubbles generated at the lower part of the cell from obstructing the electrolytic reaction at the upper part of said electrodes, thereby improving the electrolyzing conditions of the cell and in consequence decreasing the required cell voltage. Therefore, cell operation with high current density is substantially saved from the hindrance of electrolysis resulting from the prominent evolution of gas bubbles.

Furthermore, the cell bath is effectively stirred by streams of gas bubbles rising through the vertical passageway preventing highly concentrated product, for example, caustic soda from being locally deposited on the surfaces of the cathode. Intrusion of gas bubbles into the diaphragm is also restricted to facilitate the cell operation with high current density. Another advantage of this invention is that the surfaces of the anode and/or the cathode are divided into small sections and indicate very little change in the electrolyzing efficiency resulting from the varying depth of the cell bath, thus making it possible to provide an electrolytic cell provided with a deep bath and yet requiring a small space of installation.

This invention will be more fully understood by reference to the examples which follow.

EXAMPLE 1 The anodes of a brine-electrolyzing cell constructed as illustrated in FIG. 2 consisted of graphite plates each mm thick, 600 mm high and 200 mm wide. The anode plates were bored with zigzag arranged 10 mm diameter gas holes (not shown) inclined 45 upward from the diaphragm to the cell center. The cathodes were formed of mild steel nets whose back sides were fitted with asbestos diaphragms. The anodes and cathodes disposed on both sides of the respective diaphragms were spaced 10 mm from each other, a distance between two adjacent diaphragms measuring 40 mm. The cell thus constructed was operated within anode current density of Aldm The average cell voltage stood at 3.46 volts during a period of 24 to 48 hours after commencement of electrolysis.

Two adjacent graphite anodes 40 mm apart from each other were fitted with a plurality of 2 mm thick gas bubble guiding partition plates made of chlorinated polyvinyl chloride, inclined 60 upward and vertically arranged at a distance of 60 mm. The vertical gas-bubble passageway was 5 mm wide at the base and 15 mm wide at the top. When brine was electrolyzed by the cell thus improved according to this invention with an anode current density of 15 Aldm the cell indicated an average cell voltage of 3.26 volts during a period of 24 to 48 hours after operation.

EXAMPLE 2 In a water-electrolyzing cell shown in FIG. 3, two cathodes 11 of mild steel each 2 mm thick, 600 mm high and 200 mm wide were set upright. A diaphragm of asbestos cloth 12 was disposed near the outer wall of each cathode 11. An anode 13 of stainless steel having the same dimensions as the cathode 11 was erected near the outer wall of each asbestos diaphragm 12. The distance between the cathode l1 and the facing diaphragm 12 was 8 mm, and a distance between the diaphragm l2 and the facing anode 13 was 10 mm. The cathodes 11 and anodes 13 were bored with a large number of 10 mm diameter holes 14 arranged in a equilateral triangular formation at a pitch of 15 mm.

The cell of the above-mentioned construction was filled with a 10% aqueous solution of caustic soda as electrolyte and operated with a cathode current density of 20 A/dm The cell voltage indicated 3.65 volts at a temperature of 35C.

The cathodes l1 and anodes 13 of the above-mentioned electrolytic cell were fitted on the back side with gas-bubble guiding partition plates (not shown) inclined 60 upward at the rate of one plate for each row of holes 14. The vertical gas-bubble passageway was 15 mm wide. When operated under the same condition as described above, the electrolytic cell thus improved had its voltage reduced to 3.50 volts at a temperature of 35C.

What we claim is:

1. In a multiple vertical diaphragm electrolytic cell, the improvement comprising a plurality of electrode chambers, each including two electrodes having mutually facing walls which are disposed on opposite inner sides of respective electrode chambers and a plurality of separate gas-bubble guiding partition plates made of a heat-resistant synthetic resin attached to said mutually facing walls of said electrodes in an upwardly inclined condition with the lower ends thereof in a slightly separated position from said walls and with adjacent heat-resistant synthetic resin partition plates spaced from each other in a vertical direction relative to said mutually facing walls, said heat-resistant synthetic resin partition plates being dimensioned and mounted in an opposing formation so that extremities thereof remote from said walls define a vertical gasbubble passageway along the vertical central plane position of each respective electrode chamber, said heat-resistant synthetic resin partition plates being inclined upwardly relative to the central level of each respective electrode chamber.

2. The electrolytic cell according to claim 1 wherein the plurality of electrode chambers are anode chambers.

3. The electrolytic cell according to claim 1 wherein the plurality of electrode chambers are cathode chambers.

4. The electrolytic cell according to claim 1 wherein the plurality of electrode chambers comprise anode chambers and cathode chambers.

5. The electrolytic cell according to claim 1 wherein the heat-resistant synthetic resin is chlorinated polyvinyl chloride.

6. The electrolytic cell according to claim 1 wherein said partition plates define a vertical gas-bubble pas sageway which has a width progressively increasing toward the top.

7. The electrolytic cell according to claim 1 wherein the gas-bubble guiding partition plates are mounted to the electrode upwardly in a horizontally extending position.

6 the gas-bubble guiding partition plates take a curved form.

11. The electrolytic cell according to claim 1 wherein the gas-bubble guiding partition plates take a refracted form. 

1. In a multiple vertical diaphragm electrolytic cell, the improvement comprising a plurality of electrode chambers, each including two electrodes having mutually facing walls which are disposed on opposite inner sides of respective electrode chambers and a plurality of separate gas-bubble guiding partition plates made of a heat-resistant synthetic resin attached to said mutually facing walls of said electrodes in an upwardly inclined condition with the lower ends thereof in a slightly separated position from said walls and with adjacent heat-resistant synthetic resin partition plates spaced from each other in a vertical direction relative to said mutually facing walls, said heat-resistant synthetic resin partition plates being dimensioned and mounted in an opposing formation so that extremities thereof remote from said walls define a vertical gas-bubble passageway along the vertical central plane position of each respective electrode chamber, said heat-resistant synthetic resin partition plates being inclined upwardly relative to the central level of each respective electrode chamber.
 2. The electrolytic cell according to claim 1 wherein the plurality of electrode chambers are anode chambers.
 3. The electrolytic cell according to claim 1 wherein the plurality of electrode chambers are cathode chambers.
 4. The electrolytic cell according to claim 1 wherein the plurality of electrode chambers comprise anode chambers and cathode chambers.
 5. The electrolytic cell according to claim 1 wherein the heat-resistant synthetic resin is chlorinated polyvinyl chloride.
 6. The electrolytic cell according to claim 1 wherein said partition plates define a vertical gas-bubble passageway which has a width progressively increasing toward the top.
 7. The electrolytic cell according to claim 1 wherein the gas-bubble guiding partition plates are mounted to the electrode upwardly in a horizontally extending position.
 8. The electrolytic cell according to claim 1 wherein the gas-bubble guiding partition plates are mounted to the electrode upwardly in an inclined position.
 9. The electrolytic cell according to claim 1 wherein the gas-bubble guiding partition plates have a plane surface.
 10. The electrolytic cell according to claim 1 wherein the gas-bubble guiding partition plates take a curved form.
 11. The electrolytic cell according to claim 1 wherein the gas-bubble guiding partition plates take a refracted form. 